Radioactivity May Block English Shellfish From Market - New Scientist

[hatrack]

Thousands of tonnes of British shellfish currently eaten in Europe could be banned under new international safety limits for radioactivity in food, the UK Food Standards Agency (FSA) has warned.

Lobsters, cockles and scallops from the north west of England and the south west of Scotland are so contaminated with plutonium from the Sellafield nuclear complex in Cumbria that they will breach limits due to be introduced by the United Nations in 2005.

Although the new limits are welcomed by radiation experts, they are regarded as "not proportionate to the actual risk" by the FSA. And they have angered the multi-million pound shellfishing industry. Douglas Macleod, chairman of the Association of Scottish Shellfish Growers, said that limits should only be set on the basis of robust science backed by credible risk assessments. "Why should the industry be unnecessarily crucified if there is no real risk?" he asked.

EDIT

Concentrations of plutonium and related isotopes in all the shellfish sampled by the FSA between the Ribble estuary at Preston and Kirkcudbright on the North Solway coast in 2002 exceeded 1Bq/kg. Winkles from St Bees, next to Sellafield, contained 66 Bq/kg."

EDIT

http://www.newscientist.com/news/news.jsp?id=ns99996516

[NNadir]

1. This is a good one. The average 70 kg human contains 140 grams of

Potassium. This means that there are 2 grams per kilogram of potassium in human flesh. Of this 2 grams 0.0117% is Potassium-40, or 0.000234 grams. Potassium-40, is of course, radioactive, being left over from the supernovae from which we were all created. The specific activity of Potassium-40 can be calculated from its half life which is 1.277 billion years: To do this we multiply 1.277X10^9 by 31,556,736 seconds in a sidereal year and divide the natural logarithm of 2 by the result. This gives the decay constant for potassium 40 which is 1.72X10^-15. Multiplying this number by Avogadro's number we find the activity per mole associated with the decay of pure Potassium-40, we find that the specific molar activity associated with Potassium is 1.04X10^9 decays per mole, or, put another way, 1.04 billion Bequerels per mole. (A Becquerel is simply a single nuclear decay.) Now we divide this number by the isotopic mass of Potassium-40, 39.9639987 g/mole, to find that the specific activity of Potassium 40 is 2.59X10^7 Beq/gram or 26 million Becquerel per gram. Multiplying this times the amount of pure potassium 40 in human flesh, we see that a kilogram of ordinary human flesh contains 2.59X10^7 Beq/gram * 0.000234 grams = 6.06X10^3 or 6 thousand Beq of radioactivity from having potassium in our bodies. (I am ignoring the other naturally occurring radioactive elements like Rubidium, Uranium, Thorium, and Radium; all of which are found in human flesh.) This means that the most contaminated shellfish described herein are at best, have 100 times less radioactivity from the "contaminant" than normal flesh(and presumably the tissues of other life forms) has from the natural potassium.

What is missing in this debate is common sense and, as one might expect, critical thinking. It is enough to say "Plutonium" and "radioactivity" in the same sentence to create paroxysms of unparalleled stupidity.

The fishermen are right, at least on the issue of whether this radioactivity represents a health risk. This is a very dumb proposed regulation.